Embracing Open Science is critical if we are to make science more collaborative, reproducible, transparent and impactful. Open Science undoubtedly has the power to positively influence society, but its implementation is not yet universal. A revolution is required: one which opens up research processes and changes mindsets in favour of a world where policies, tools and infrastructures universally support the growth and sharing of knowledge. Research libraries are well placed to make that revolution happen, and LIBER's Open Science Roadmap outlines the specific actions libraries can take to champion Open Science, both within and beyond their own institutions. As we explain in detail throughout this document, libraries need to advocate for Open Science locally and internationally, to support Open Science through tools and services and to expand the impact of their work through collaboration and partnerships. LIBER has shaped its 2018-2022 Strategy to support and enable Open Science and it is our hope that this Roadmap will help Europe’s research libraries to do the same. This document was written during spring 2018, when the Open Science Policy Platform (OSPP) produced integrated advice for the EC and key stakeholders. People from across the LIBER community translated the OSPP recommendations for libraries and combined them with suggestions drawn from their own expertise and experiences.